Science shows these are the only kinds of bug spray that actually work

You're actually supposed to spray it on your hands and transfer it to your face.Gregory Shamus/Getty ImagesUsing bug spray is one of the best defenses we have right now against bug bites — as well as certain diseases like Zika.

The virus is spread by aggressive mosquitoes that bite during the day, and in addition to wearing long sleeves and pants, or staying inside, the US Centers for Disease Control and Prevention recommends anyone over two months old should use insect repellent in areas where mosquitoes are present.

Consumer Reports recently came out with its annual bug spray buying guide, and found that only three ingredients are effective at warding off mosquitoes for at least seven hours. Roughly in order of effectiveness, those ingredients are: DEET, picaridin, and oil of lemon eucalyptus.

But it's crucial to buy the right concentration of these ingredients, CR notes, since lower percentages of these ingredients did not do well. The effective concentrations are:

15% to 30% DEET

20% picaridin

30% oil of lemon eucalyptus (But the CDC says you shouldn't use this ingredient on kids under three years old.)

Products marked "natural" or with active ingredients other than these three were not effective at protecting people from mosquito bites, according to CR. (They're also not necessarily safe.) Combination sunscreen-bug sprays didn't work, either. And they actually had people stick their arms in mosquito chambers to test them out.